Transparent mariner&#39;s compass



A. LIETZ -TRANSPARENT MARINERS COMPASS Filed April 1l. 1927 2f 6 m m :'H v

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Oct. 20, 1931.

'Patented Oct. 20, 1931 UNITED STATES ADOLPH LIETZ, OF SAN FRANCISCO, CALIFORNIA TRANSPARENT MARINERS COMPASS Application filed April 11,

f the compass card is filled with a high Y e alcohol spirit, and that unless some s eciai means is provided, any jar given the compass bowl will tend to cause the compass card to float oft its support and thereby interij e with the proper operation andconveuient reading of the card as a direction indicator.

Another object of' the invent-ion is to so arrange the expansion'chamber used as to prevent'any interference with the ligln'.- which is placed below the compass, to thereby prevent accidental misreading of the compass.

@ther objects of the invention will be apparent as the description proceeds.

i An embodiment of the invention is shown j top chamber r19 and a bottom chamber 20 in the accompanying drawings in which the same reference numeral is applied to the same portion throughout the several figures of the drawings and of which there may be modiications.

Figure l is a vertical sectional view through the compass bowl showing the gimbal supports 'for the same,'

Figure 2 is a bottom plan View of the combowl taken with the lower portion thereof cut away, as indicated by the line 2---2 Figure 1, the gimbal supports for the bowl bein also shown.

The compass bowl. is indicated at 1, and

consists of a cylindrical shell with an in-V turned flange 2 forming a portion of the bot flange 3 by means of several screws 6, a liquid. tight )omt hemp; produced by the flange 3,

the glass 4 and the ring 5.

ordinary mariners compass the bowl containf 1927.` serial No; 182,558.

A bar 7 is secured to the inside of the flange 3, and rests upon the top of the glass 4, said bar also supporting the compass pivot 9. A shallow convex shell 8, or it might be a solid body except that the weight would be thereby increased, serves to reduce the .quantity of free liquid under the card yand .thereby .prevents pulsations of the liquid from occurring to `an extent vlikely to unseat the card. .y r l The compassis of any well-known type for this particular work.v and consists 4of the float`10, compass card 11, float bearing cone 12, and a plurality of tubes 13, 14, 15 and 16 ywithin whichthe compass needles are mounted. v f A ys Thetubeskare connected to the card 11 by means of lsmall Wires 17 and 18 in each instance, and', the weight of the compass card when immersed in the liquid usedV in the compass box is very nicely regulated to about -90 grains when immersed to give the compass cardthe necessary stability while at the same time reducing the vweight on the needle point to arminimum. t Surrounding the flange 3 just under the bowl is a double expansionring made up of a connected thereto. These chambers are each complete circles and are formed of thin sheet metal so as to give the desired flexibility.

i The material of which' said chambers are made usually being spring copper or brass,

V,and the annulus thus produced .is connected pass into andout the expansion chamber.

The compass is covered with a glass 25 vwhich is held in place bymeans of a gasket 26, and flat'vring 27, the latter being held in place by the screws 28. 1

` Atjthe sides of thecompass there are two integral gimbal arms 29 andSO to permit the compass` to be supported in gimbal rings to hold the compass level'at all times.

f In order to weight the compass bowl to `.hold itV level there is a shield depending therefrom as indicated at with an inturned ,'tion. y Neither the expansion ring 'nor the "sma'lleramete tjiplxrte cover en *the bottom ef said Bange 32, the lower edge of which is 11pturned as indicated at 33 to form a receptac e for an annular mass of lead or other material, as indicated at 34. This weight lowers the center of gravity of the compass bowl and makes it stand level in the gimbal rings with more In actual practice a lamp o'f some kind is placed so that its rays will shine through-the compass and thereby enable the marinai' to determine the bearing of the card at an moment without the aid of aznytmilsifle Should any jar strike the compass bowl the movement of the liquid will be taken up by the .aid of the expansion rings forming the 1'9 and .20. Since A'tle quantitl of A'fl under the float it() and over ther ell 8 issmall tlrere will be less tendency of *the inside the bowl to move in sue'fh a way to dislodge the card from its 'proper posi1 Salone will redncet'he card otat'ion when'the c ass bowl is 'jarred iheavi'ly.

aving thus described my invention, -what I desire Vto by Letters Patent df the United 'States is Ias follows, but modi'catismay vbe madein earrying'out'the invention as sliovvnii the drawi'ngs-andinthe a'bove particularly described form thereof, 'within the ,purviewof the annexed claims,

1. In a marinersL ss flfe class dev rrlcalshell ha'v'n Hanse, `a. cylindrical ,shel'l Io r ependng imm said flange,

apin'turn l .Elias c 31,11 for retaining ma -gisss pldte,atransverse ar-em the upper side ef 'under said Haat, a compass card and rsaid small shell and under sa'id intu'med opentubes in'sad ange and 'Fixedto as n saifxpmvn Lehm t2, In a urar'ine'r's vcompass oae class described, `a spil-'m chanrer having a diametricall;I redueeldepressedbottmnportemftrmrsparent covers sealed in *the top'and bottom of said dlxam'ber,-anexternafl 'anmlar expansion chaniber surrounding said reduced 'bottom and communicating "inte `aail' Lsrpirit chamber, a compass oat pivoted above said d bottom portion, :and a 1shrield beneath said Boat.

In a -marines compass of the class described, a spirit hamber with a transparent Ycoverm'xlhaving a diametrical'ly reduced depressed 'gortionvrth a 'transparent 'central hieldto orm a -sprt chamber with a fbpttorn, a pivot ensaill liield, *compass *float pivoted 'on `seid pivot, and 

